pluck up the courage
screw up the courage

Eventually I plucked up all my courage and told him.

Only he went round looking for you and she plucked up courage to tell him.

I've been trying to pluck up courage to say this for weeks now.

A year later, I plucked up my courage and became pregnant once more.

She still looked pale so I plucked up courage to speak.

I waited, trying to pluck up courage to approach her.

Finally, I plucked up my courage and called a driving academy.

Finally I plucked up my courage and went out to see what had happened.

I'm sure I shall never pluck up enough courage to speak to anyone!

But the boy plucked up his courage and asked to go to the park to knock a football around.